If $a+b+c=9$ and $a b+b c+c a=-22$, then the value of $a^3+b^3+c^3-3 a b c$ is:

1323

If x + y  = n

then, $x^3 + y^3$ = n³ - 3 × n × xy

If $a+b+c=9$

$a b+b c+c a=-22$

Then the value of $a^3+b^3+c^3-3 a b c$= ?

If the number of equations are less than the number of variables then we can put the extra variables according to our choice = 

So here two equations given and three variables are present so put c = 0

If $a+b=9$

$a b=-22$

Then the value of $a^3+b^3$= 9³ - 3 × 9 × -22

Then the value of $a^3+b^3$= 1323